This application is a continuation-in-part of application Ser. No. 06/898,271, filed Aug. 20, 1986, now abandoned.
Earthquakes impose cyclic lateral forces on buildings and structures causing them to vibrate, and thus to deform and respond dynamically. Presently there exists a variety of conventional structural systems for resisting the earthquake-induced forces in the structures. In addition, there presently exists a number of patented apparatuses for improving the expected earthquake response performance of buildings or structures.
Conventional lateral force resisting structural system in seismic design include moment-resisting frames, braced frames, and shear walls. In recent years, the eccentric-braced frame, K-braced frame and other systems have been successfully proposed as alternatives for resisting lateral loads. Braced steel frames are known for their efficiency in providing lateral stiffness. Conventional concentric braced steel frames are nearly rigid. Ductile moment-resisting space frames designed to resist earthquake forces are typically flexible and these buildings or structures experience large deformations causing both nonstructural and structural damage during severe earthquakes.
Other apparatuses that are superficially similar to the apparatus of this invention include U.S. Pat. Nos. 3,605,953 (Caldwell, et al.), 4,042,651 (Gaurois), 4,117,637 (Robinson), 4,409,765 (Pall), and 4,545,466 (Iseki, et al.).